The present invention relates to an electromagnetic relay having high sensitivity, on armature release. In this type of relay, the mobile armature has a normal position in which it is magnetically held against two pole faces by a part of the flux of a permanent magnet; the remainder of this flux, which is generally the greater part being shunted by a magnetic shunt. The release of the mobile armature is obtained by reduction or cancellation of the flux circulating in the armature by means of an opposing flux generated by a control winding whose magnetic circuit includes the mobile armature and the magnetic shunt. The mechanical effect produced by the release of the armature is amplified by a trip spring which causes the opening of the armature.